White screen v1.44

I have a Dell Inspiron E1705 with Windows Vista 32 bit, NVIDIA GeForce Go 7900GS, Core 2 Duo 2.0 GHz processor and 2 GB of RAM. I will be playing a game, and everything is working great. I get up and go away from my computer for a few minutes OR I open a new Window full screen, and when I get back to SE5, the window is white. When I click on the SE5 window, I get the following error message: Access violation at address 004738C1 in module 'SE5.exe'. Read of address 00000000

I don't have a screen saver set up. When I bring up task manager, it says the game is running. NVIDIA driver is 162.22. I have my diplay set at 1280x1024 32bit. I run the game at 1024x768 16 bit. I've tried running the game at 32 bit and at different resolutions. I've also changed my display resolution to 1024x768 both 16 bit and 32 bit color. It happens every time.

Any help or advice would be greatly appreciated.